Widespread Hepatitis C Treatment Has Led to a Shift in HCV Genotypes in Spain

By Liz Highleyman

It is widely recognized that people with hepatitis C virus (HCV) genotypes 1 or 4 do not respond as well to interferon-based therapy as individuals with genotypes 2 or 3; this is true for both HIV-HCV coinfected patients and those with HCV alone.

As a growing proportion of patients receive treatment, the distribution of genotypes in a population can shift toward the harder-to-treat types, according to a presentation last month at the 16th Conference on Retroviruses and Opportunistic Infections (CROI 2009) by Eugenia Vispo from Hospital Carlos III in Madrid, Spain.

The researchers identified all HIV-HCV coinfected patients undergoing regular follow-up at their institution, and assessed the proportion treated for hepatitis C and the annual distribution of HCV genotypes over the past 5 years.

Results

A total of 653 HIV-HCV coinfected patients received follow-up care since 2004.

486 patients (74%) were treated with pegylated interferon plus ribavirin.

Among these, 28% achieved sustained virological response (SVR): 65% for patients with HCV genotypes 2 or 3, and 21% for those with genotypes 1 or 4.

Genotype 1 remained fairly stable, at around 30% for 1a and 25% for 1b.

Genotype 2 also remained stable at a much lower proportion, 1% to 2%.

Genotype 3 decreased notably, from 25% in 2004, to 22% in 2006, to 16% in 2008.

Conversely, genotype 4 increased over the same period, from 17% in 2004, to 23% in 2006, to 27% in 2008.

"The wide use of hepatitis C therapy in this cohort of HIV-HCV coinfected patients seems to have influenced the current distribution of HCV genotypes," the investigators concluded.

They noted that many of the new directly targeted anti-HCV agents ("STAT-C") in the development pipeline have been designed to be active against genotype 1, which is least often cured with pegylated interferon/ribavirin. For some of these drugs, subtypes 1a and 1b show evidence of differing susceptibility.

While these new therapies have not yet been tested in coinfected patients, knowing the distribution of HCV genotypes in this population may give some indication of their likely effectiveness.

3/27/09

References
E Vispo, A Madejon, P Tuma, and others. Effect of a Widely Used HCV Therapy on the Current Distribution of HCV Genotypes in a Large Cohort of HIV/HCV-co-infected Patients in Spain. 16th Conference on Retroviruses and Opportunistic Infections (CROI 2009). Montreal, Canada. February 8-11, 2009. Abstract 844.